In recent years, HDMI standard has been known as a standard for baseband video/audio data transmission/reception systems. Baseband refers to be being uncompressed.
Video data is transmitted using three channels in HDMI standard. In addition, audio data or data used for control is time multiplexed to each video data and transmitted (e.g., cf. Non-Patent Literature 1 and Non-Patent Literature 2).
FIG. 9 shows the configuration of a transmission/reception system 101 having a configuration compliant with HDMI standard. The transmission/reception system 101 includes a transmission device 102 and a reception device 103. Digital cameras, video cameras, and DVD players etc., correspond to the transmission device 102, and television receivers and monitors etc., correspond to the reception device 103.
The transmission device 102 is a source device, and includes a microcomputer 102a, a video output circuit 102b, a TMDS output circuit 102c, and a transmitter 102d. The reception device 103 is a sink device, and includes an information storage 103a, a TMDS input circuit 103b, a frame memory 103c, and a synchronization signal generation circuit 103d. 
In the transmission device 102, the microcomputer 102a reads, through a DDC (Display Data Channel), EDID (Extended Display Identification Data) stored in the information storage 103a formed with a ROM of the reception device 103, and examines which specification of HDMI standard that can be handled by the reception device 103. In the EDID, for example, video format in which the reception device 103 can display is described. The video format is specified by a VIC (Video Identification Code) (cf. Non-Patent Literature 2 for detail). The video format includes a resolution and a field rate.
In addition, the microcomputer 102a performs signal-processing control in the device, and, for example, performs a control of reading out recorded data from a recording medium included in the video output circuit 102b in the device and loading video data and audio data on a memory. The microcomputer 102a generates a digital video signal after receiving the EDID from the reception device 103, and generates a VIC specifying the video format of the digital video signal. The VIC is transmitted in a packet named AVI InfoFrame.
The TMDS output circuit 102c performs, for data of each transmission channel, rearranging, encoding, and parallel serial conversion of uncompressed data outputted from the video output circuit 102b. The transmitter 102d outputs serial data to a transmission path with TMDS (Transition Minimized Differential Signaling) method.
In the TMDS transmission path, three data channels (DATA0, DATA1, and DATA2) and one clock channel are used. In each data channel, video data of one of R-data, G-data, or B-data, or one Y-data, Cb-data, or Cr-data, audio data, and control data are converted to differential signals and transmitted by the transmitter 102d. The differential signal is a signal that represents Hi/Lo in a single signal as voltage difference of two signals. The video data is assigned to a display period and is transmitted as raster scan data. The audio data and the control data are assigned to a blanking period that is vertical blanking period and horizontal blanking period, and are transmitted as packet data. The control data is transmitted as an AVI InfoFrame packet.
In the reception device 103, the TMDS input circuit 103b receives TMDS data and clock from a receiver that is not shown, performs serial parallel conversion thereon, and then decodes each data. The decoded video data is outputted together with H-sync and V-sync signals and pixel clock generated by the synchronization signal generation circuit 103d, based on an analysis result of the transmitted clock and AVI InfoFrame packet. The audio data decoded by the TMDS input circuit 103b is used for outputting audio.
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